Math help - Fantasy Baseball Cafe 2014 Fantasy Baseball Cafe
100% Deposit Bonus for Cafe Members!

Return to General Talk

Math help

Moderator: Baseball Moderators

Math help

Postby Broncmet724 » Fri Mar 14, 2008 10:15 am

This is a dumbed down version of OBP since with some projections you don't get all the stats you need. I know it's not accurate, but it's not like projections are completely accurate anyway.

What I'm trying to figure out is walks. The simple formula is (Hits + BBs)/(ABs + BBs) = OBP. With one set of projectiona I have, they give me the Hits, ABs, and OBP, and I want to calculate BBs.

I've played with the formula, but it's been 20 years since I took math in high school and apparently I am more rusty than I thought. Can some give me the formula to figure out the BBs in this case knowing the other values?

BB = ?
Image
Broncmet724 Beginner
Major League Manager
Major League Manager

User avatar

Posts: 1754
Joined: 8 Apr 2003
Home Cafe: Baseball
Location: On the outside looking in

Re: Math help

Postby KCollins1304 » Fri Mar 14, 2008 10:26 am

(Hits-AB*OBP)/(OBP-1)=walks

Did that pretty quick on a scratch sheet of paper, I'm pretty sure it's right though.
Image
KCollins1304
Hall of Fame Hero
Hall of Fame Hero

User avatar
CafeholicCafe WriterCafe RankerMock(ing) DrafterEagle EyePick 3 Weekly WinnerLucky Ladders Weekly Winner
Posts: 5089
Joined: 29 Dec 2005
Home Cafe: Baseball
Location: Charlotte, NC

Re: Math help

Postby bigh0rt » Fri Mar 14, 2008 10:43 am

The approximation of it is going to be BB = OBP(AB + BB) - H

But OBP only takes you out to the thousandths place on most sites, so it's not going to give you the exact number of BB.

e.g. Carlos Beltran (Career)

BB = .354(5113 + 591) - 1433
BB = .354(5704) - 1433
BB = 2019.216 - 1433
BB = 586.216

He's actually drawn 591 BB, but since OBP is rounded to the thousandths place, it's going to be an approximation. Either that or me not having my coffee this morning is killing my brain. :-b
Image
bigh0rt
Hall of Fame Hero
Hall of Fame Hero

User avatar
CafeholicCafe WriterGraphics ExpertMock(ing) DrafterEagle EyeInnovative MemberCafe MusketeerWeb SupporterPick 3 Weekly Winner
Posts: 24816
(Past Year: 357)
Joined: 3 Jun 2005
Home Cafe: Baseball
Location: Crowding The Plate

Re: Math help

Postby Broncmet724 » Fri Mar 14, 2008 11:35 am

KCollins1304 wrote:(Hits-AB*OBP)/(OBP-1)=walks

Did that pretty quick on a scratch sheet of paper, I'm pretty sure it's right though.


Ok I get a negative value with that since ABs will be more than H, and OBP - 1 will be negative also.
Image
Broncmet724 Beginner
Major League Manager
Major League Manager

User avatar

Posts: 1754
Joined: 8 Apr 2003
Home Cafe: Baseball
Location: On the outside looking in

Re: Math help

Postby Broncmet724 » Fri Mar 14, 2008 11:42 am

bigh0rt wrote:The approximation of it is going to be BB = OBP(AB + BB) - H

But OBP only takes you out to the thousandths place on most sites, so it's not going to give you the exact number of BB.

e.g. Carlos Beltran (Career)

BB = .354(5113 + 591) - 1433
BB = .354(5704) - 1433
BB = 2019.216 - 1433
BB = 586.216

He's actually drawn 591 BB, but since OBP is rounded to the thousandths place, it's going to be an approximation. Either that or me not having my coffee this morning is killing my brain. :-b


Yep but the problem is the BBs in the middle of the parenthesis, I won't have the value for that. And I tried to carry it a bit further

BB = OBP * AB + OBP * BB - H
then
BB - OBP * BB = OBP * AB - H
then
BB - BB = OBP * AB - H / OBP

That's screwed up, but that's just me O:-)

Thanks for the help tho
Last edited by Broncmet724 on Fri Mar 14, 2008 12:05 pm, edited 1 time in total.
Image
Broncmet724 Beginner
Major League Manager
Major League Manager

User avatar

Posts: 1754
Joined: 8 Apr 2003
Home Cafe: Baseball
Location: On the outside looking in

Re: Math help

Postby KCollins1304 » Fri Mar 14, 2008 11:57 am

Broncmet724 wrote:
KCollins1304 wrote:(Hits-AB*OBP)/(OBP-1)=walks

Did that pretty quick on a scratch sheet of paper, I'm pretty sure it's right though.


Ok I get a negative value with that since ABs will be more than H, and OBP - 1 will be negative also.


The numerator and denominator should both be negative, then they cancel each other out to give a positive number.
Image
KCollins1304
Hall of Fame Hero
Hall of Fame Hero

User avatar
CafeholicCafe WriterCafe RankerMock(ing) DrafterEagle EyePick 3 Weekly WinnerLucky Ladders Weekly Winner
Posts: 5089
Joined: 29 Dec 2005
Home Cafe: Baseball
Location: Charlotte, NC

Re: Math help

Postby Broncmet724 » Fri Mar 14, 2008 12:04 pm

KCollins1304 wrote:
Broncmet724 wrote:
KCollins1304 wrote:(Hits-AB*OBP)/(OBP-1)=walks

Did that pretty quick on a scratch sheet of paper, I'm pretty sure it's right though.


Ok I get a negative value with that since ABs will be more than H, and OBP - 1 will be negative also.


The numerator and denominator should both be negative, then they cancel each other out to give a positive number.


True, but the first time I plugged the numbers in I got an obscene number of walks

I'll use one guy's projections of 173H 589AB .383OBP

(173-589*.383)/(.383-1)=BB

(-52.587)/(-.617) = BB

85 and change = BB

I assume I multiply the 589 * .383 first then subtract from the 173. It works out that way.

Thanks K
Image
Broncmet724 Beginner
Major League Manager
Major League Manager

User avatar

Posts: 1754
Joined: 8 Apr 2003
Home Cafe: Baseball
Location: On the outside looking in

Re: Math help

Postby bigh0rt » Fri Mar 14, 2008 12:24 pm

Duh, I forgot to finish the equation :-b

BB = (OBP*AB - H)/1 - OBP

should be the correct formula.

Using Beltran, again, we get...

BB = (.354*5113 - 1433)/1 - .354
BB = (1810.002 - 1433)/.646
BB = 377.002/.646
BB = 583.5944272
... which still isn't our desired 591, but again, I imagine that's likely due to the rounded OBP we used. His actual OBP is 0.35483871

Using that extended OBP, we get...
BB = 590.2327

EDIT: The discrepancy can be attributed to the calculator I'm using rounding itself after it runs out of places. I'm using a scientific and not a graphing.
Image
bigh0rt
Hall of Fame Hero
Hall of Fame Hero

User avatar
CafeholicCafe WriterGraphics ExpertMock(ing) DrafterEagle EyeInnovative MemberCafe MusketeerWeb SupporterPick 3 Weekly Winner
Posts: 24816
(Past Year: 357)
Joined: 3 Jun 2005
Home Cafe: Baseball
Location: Crowding The Plate

Re: Math help

Postby KCollins1304 » Fri Mar 14, 2008 12:44 pm

bigh0rt wrote:Duh, I forgot to finish the equation :-b

BB = (OBP*AB - H)/1 - OBP

should be the correct formula.

Using Beltran, again, we get...

BB = (.354*5113 - 1433)/1 - .354
BB = (1810.002 - 1433)/.646
BB = 377.002/.646
BB = 583.5944272
... which still isn't our desired 591, but again, I imagine that's likely due to the rounded OBP we used. His actual OBP is 0.35483871

Using that extended OBP, we get...
BB = 590.2327

EDIT: The discrepancy can be attributed to the calculator I'm using rounding itself after it runs out of places. I'm using a scientific and not a graphing.


That's the same equation I gave him initially, just with the top and bottom multiplied by -1. It looks cleaner w/ yours though with the positive numbers.
Image
KCollins1304
Hall of Fame Hero
Hall of Fame Hero

User avatar
CafeholicCafe WriterCafe RankerMock(ing) DrafterEagle EyePick 3 Weekly WinnerLucky Ladders Weekly Winner
Posts: 5089
Joined: 29 Dec 2005
Home Cafe: Baseball
Location: Charlotte, NC


Return to General Talk

Who is online

Users browsing this forum: No registered users and 2 guests

Forums Articles & Tips Sleepers Rankings Leagues


Today's Games
Tuesday, Sep. 2
(All times are EST, weather icons show forecast for game time)

Cincinnati at Baltimore
(7:05 pm)
Detroit at Cleveland
(7:05 pm)
Boston at NY Yankees
(7:05 pm)
Philadelphia at Atlanta
(7:10 pm)
NY Mets at Miami
(7:10 pm)
indoors
Toronto at Tampa Bay
(7:10 pm)
indoors
Milwaukee at Chi Cubs
(8:05 pm)
Chi White Sox at Minnesota
(8:10 pm)
Texas at Kansas City
(8:10 pm)
LA Angels at Houston
(8:10 pm)
Pittsburgh at St. Louis
(8:15 pm)
San Francisco at Colorado
(8:40 pm)
Seattle at Oakland
(10:05 pm)
Washington at LA Dodgers
(10:10 pm)
Arizona at San Diego
(10:10 pm)

  • Fantasy Baseball
  • Article Submissions
  • Privacy Statement
  • Site Survey 
  • Contact